[Bug middle-end/54846] New: -ftrapv doesn't work in 64-bit mode

["mikulas at artax dot karlin.mff.cuni.cz" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54846

             Bug #: 54846
           Summary: -ftrapv doesn't work in 64-bit mode
    Classification: Unclassified
           Product: gcc
           Version: 4.7.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: mikulas@artax.karlin.mff.cuni.cz
              Host: x86_64-unknown-linux-gnu
            Target: x86_64-unknown-linux-gnu
             Build: x86_64-unknown-linux-gnu


-ftrapv flag should generate a crash if integer overflow happens. But it
doesn't
work in 64-bit mode.

Try this:

#include <stdio.h>

int main(void)
{
        int a = 0x70000000;
        int b = 0x50000000;
        int c = a + b;
        printf("%x\n", c);
        return 0;
}

When compiled with "-ftrapv -m32", an abort happens. However, when compiled
with "-ftrapv -m64", there is no crash. If we look at assembler output, we see
that it uses function __addvdi3 to do the addition. This function is for 64-bit
numbers, not for 32-bit. If I replace __addvdi3 with __addvsi3, an abort
happens correctly.